SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f311f327cddc804de2336a276f1fa280ed70dea743229f4fbf559d1300d295e' 
  AND token = 'Nq5kBDEJYHmP+OudOgvyxeiJU6vXWweMY5wBHvSwaXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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