SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ee7fc8a42ea36b3bce85212cf4a9fb318691e63338726121d70c9109e6c56d0' 
  AND token = 'hE4VdSBpdRTRjwn+ydjdURNNlsl4ixWD8UlRti/oX0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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