SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87ad05ef96211e909930173a72bcb55b5e92eb512144d1921ebe771b8a69debf' 
  AND token = 'AabZ31mdDqMUkM+QLmr27PQqlWVrsI2ky4b/0xYOxag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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