SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b9319d9db61a4353d23770adce7c289e5d839703db1f2f859836e530ab5d6a6' 
  AND token = 'PCbZtOBpuLumtWr1yUYw5RoylY6xSp5qIKnnLheRTYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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