SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47f2b0cae41f797d57617f7d279dff9ab6c838719a3fb125adea0e065661538a' 
  AND token = '3RFPabVclueqJMytFuyQ5jtvybaHfabxDd9ZQ9hCKIg=' 
  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"
    }
  }
}