SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '58adc2fdc0c646ffaa2229caa430a8a4ab39774fb2cb862ee88f15c81ab0af34' 
  AND token = 'jyRnsBB7B8+i/OhA7Xv+c6X7+5y1Ryv9uFZjo0Dt3cg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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