SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8973668178bb68f4883cf57671a7270e3d9ba7255ddeb8d9cd2bae6e8f74624b' 
  AND token = 'sTA6MtaraHSICDvxz8px/8s9tNqkWUtnMlNOAvS2z1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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