SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ecfb7d81748136f5c11b47eb8052ac968a60ec5c909769fe009046be00819ab' 
  AND token = 'jhdnALndvHRu0L1ErLwAG2wL5amiqUDSSOKfFA0pkQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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