SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f789a03fbb3a0ec605956528e527fe58c3cacaed4520302fd06ad66a768c357' 
  AND token = 'o7ykIR1fH6iczwh5y/1gvdGXKGmLcm27nmVqAvIrue4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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