SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddbb521499bfdea00a673eacecd61ff25fd44896c7d1a83477853dfe1d6b48d1' 
  AND token = 'z1h2VapbxzLAYqC2AMZQs27Sb8xreHpiZr8TvayrAnI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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