SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e598e65f14a064dd417a3e3351edf0243b019bad92ccae3e42754a4d941fa5fd' 
  AND token = 'MNqmHLTrdtSVDvee6TexJ7Gp5YkAa5NCbLNMlJQonV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}