SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '244b0f526892ce6976f463d0f6c10a748bec0539f179fefdd68ae9fac5021f9c' 
  AND token = 'dDyy7p1zLYg/XqKJ5Qgvr70kmB4tSql9kZUXNMZZhEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}