SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31938f25a98570e6001e2caf78ae9517b4810dffcc9b41a805cac1ddefc25e9c' 
  AND token = 'pJAGlFtIvVzzOYua3r0wdLHMvSweQ2KjNvZVbVotfkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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