SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f30f951b2719430810885179d894122898d58bae9e7fc0770eeec4209c4a5caf' 
  AND token = '3OxcKTDUEFVyFV0Q6f9Mct1KtEqZc00Zqi5rcx3ichU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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