SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c30943c2625bdf9b2d32e56a490cedfe57b20ae7abe3ed4a0a8c98aa837fe347' 
  AND token = 'BXcQusUmOMXQhcfbMh28XqqB4lmQy96nm2KN2QrEqfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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