SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7638c989cec78b78be198bf4b24bf3303ae3a63a363d28c05f53129ad92e3949' 
  AND token = 'MBKg72c+nuwqFIm/AQRFbGlk4PGEYatUGd18uyKtvtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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