SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c54274de7bc6d2bbc1aa0900cc30a22d4863e0a35019827c4d71bf8ad3b0931d' 
  AND token = '9n5hIU2cQFoFM78uUuOzhyK6fqVrdbib4zHcKZf1FEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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