SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66f2c0732a0bb6da8e7f5a53025faf0c99c56f1a9fe50d8ec02e600b41c856ee' 
  AND token = 'c4ZWr1/kOs8Bo51m49vh4ajoPRvGPziLUWimf50BNSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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