SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d7645041d60b35c40f58a9a74ef800d15031b803c0b7ec6a00e98cbaff57f84' 
  AND token = 'e9teE2lo9QjM8dTRirgXNj9//nYsBzCV31DS/D0uQao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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