SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b9acb5bea67db5158fe7b84c4181693e3099999e7bc48e81924af423e764f0a' 
  AND token = '3fDvhmeG4mD0JbOA7E1BhqQ5Qdq/MzqhfJ+bgy/vZ3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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