SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e868f4ce3ad955d1db5b8de91bc29ba8e83f49f7b0384d573b11dac9cfc9eba6' 
  AND token = 'NAShXX64WgQmHdqRw8EmTBmfoNhxwAIn+zneCTCjk/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}