SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e74f2fec7ce89faa8f33e14a13ffc989011759ab15888bfbac4f79e1c572a649' 
  AND token = 'NEEyxShnROhAXxjuVOpQpp5TIbI4fxpOXv5R6N0i9Zc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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