SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c085afe83bae3af25cd853d90578e3c7e37286809ec5206ba50bb202e3755d78' 
  AND token = 'E7BViY54FeBhCtL7l6JGvmdj3r9YV+JvcWYJD/mIHFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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