SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '20cf29ea6824c39a219ae0c6faa02af013f80d94b599301cfd81d5888753dee5' 
  AND token = 'pGhKgTYB/FVxbn7acqCjWhPPo9uUM6IjaH8yoY2AadM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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