SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dd971ddb502dbefc22d7055ac2d61235a9854307b9c34a2be01d4d88efad327' 
  AND token = 'KA5HL+aieupFTLPACcWZv5uWSMGT2s9cOZWJ9lcChNg=' 
  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"
    }
  }
}