SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f71f5f93dcfc443b6ef8f8d63d1b78c5ec0954dbeba2f3adb6f193e3d852e842' 
  AND token = 'O5UkXVRVvpTbQncM0SO0vazoj7YaRsuia/KkxgyHMxo=' 
  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"
    }
  }
}