SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90ea280b0f15f9188988ab26dc6b87b801c3129db9d0b943c37d2064b9e37bd3' 
  AND token = 'kjx1sHwaTQULEGx/gYbYa8P4Qu3kXaEkjd/10B3CGdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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