SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cabefa876d7d6129cf1db294463a90171767b89a8f445754b5a8d474b23cb743' 
  AND token = 'w9TXxvcNuB6r7OHU0NnHdasSgsh8ZFZtBmN+ab+zd78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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