SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb29662995a1d0f669f83c185485c25837cf5eaca37856aa2e24dcd81ab66164' 
  AND token = 'g4uy3+PsaRWjkYyjTUNl0Gh0VN7QlAd8/Q3zsD3ZVqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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