SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1d8fc673908a02c3d5f258437159075cb330f8e6c7f6029b796819aca2b27dd' 
  AND token = 'Ltk++V/y2gBviDYa86z1gDwugS+YZI6Yz66pJIfvAtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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