SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8c5e4beb47b6d41b8df7c56fb32e219523fd33588ff49f0960bcd5db788621a' 
  AND token = 'iO9HE75oQN7wDNaVCXVbEgYE1KJ0ABeqzB7PN+EHunw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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