SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '993364d6838d560de6238ae66606fa30e08b9d930a9e71c4183fa17e96754f5a' 
  AND token = 'emxlQR3V7mBbZWZYpkSjlrL9ZUHLSGIJweip1PJZEas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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