SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8aa1bcc1e38010521676c0ec6324484715431df3bd4537331deb77a20c6a4345' 
  AND token = 'SEukkTWwxLq0qstP7KW8zWZ0ssSPOBJ3AvbgGo6W4JM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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