SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b109b8997d5d09bba173395c5a984f3c65338dc7e51bfffe7ccdb65b5d5fef4e' 
  AND token = '53s35FCKAOCvDfiOZ/mwBAGpSOruUMwqKCwj0xM4+UQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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