SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '508c9170258794946fc754d741fd55fcf1c6bca35d2eb55989ba0d1b3df7656c' 
  AND token = 'fpQCkCYwEhUnZBx7N/EASHKdc+5gBebxrjYak3rRq9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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