SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71735ef4535d1003c1e41892ec83e2a4fd9fc60370f669ca177a6b35b0d8dab4' 
  AND token = 'O78OEpaP/K/nFS7l2nKKPGwJrFoJ2VWm+Xo0jiGEZ+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}