SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0988be0e4230e0cf67a919dc93485172f8d512fdcf45e21747fd5c28fa01f04' 
  AND token = 'yIlD/uHlpc1n6Y/R1TYNG3VmaxVVQZLOw3oPtYrlj6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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