SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9a0f3e34eed11cccb1f93ed4ee08a6af8eb34682c026fe17071533ea6a6e56e' 
  AND token = 'oHLF742xgBp/M5xWAFt7fBBDomMHQlJN4id+xxlddpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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