SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f7a8c1cf1dcfd869d512af2df58b20a442edac19a37676a2bd626382ace5ec3' 
  AND token = 'SW7qGc/8OJJ+DOU3JjNIWCJkH/60eaAzC8a6yfkZfAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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