SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2f2a57bb076ea13baa6cd9370856c0c07ba7136cd1adc14baeb13ac850195d6' 
  AND token = 'qKG5808BP/5VUOXjY3adS1MSqzYvOgQY7vVKVKMjLJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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