SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b278d99342c6dde6fffdfc7b1e1284df5d35959dd4718feaaa1bcb1e18428b4' 
  AND token = 'iy3BwvJTaAM/Af6hNRTVdSmDZvbR8JxCY26Qjz3b3Y8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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