SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1eb49c0833b6323e5844e49bbacb089138dae882ce54756096b2371db239a6f' 
  AND token = 'T8jhhqPQPBmLQT0H67AOfRdWbAERARlev/puSCSf5Uo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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