SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ddd1dfe1cd7a8f31c4a715f6df1c6387d43a158651a8aecf897cec56611c663' 
  AND token = 'QaEwR8lDl80uxeDlqdNFON1kkcazYndciiCWJpn5gsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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