SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c968473800e5a822b85f80452d48569ff2bc87fcfd3f5dbc279e888727da447' 
  AND token = 'XyDEamt3Mav3jmfJGQRZ9wJroc3kOZ/MPXgsPgjeFVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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