SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57aac918f1066ceab8464b5a46686f51369435bfe3c5e2583b19355247290431' 
  AND token = 'n5G6wp7D5wAsN5he+BGr4SWmjYYKSjX1QEHYKH26N+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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