SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '84db9f858a9df007f0901f0216ee20143c6321c2ac25d6a684adc4e3dcf6d399' 
  AND token = '0gMVqqcl1ZlWShouWQoY2fTz8lZyUtmV9zm2grbt5HI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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