SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f0923c5db0d19dfcec4235556e148261106db6867aeb54677aaa03431d80e53' 
  AND token = 'NxTjlBA7B7E4RwXWpHC7UgYwU7zm7SllzG9gdZT4FoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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