SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ff7c838034517bcf96ba50896c43edf049b8ce721e0c30b0cf2881e14bccf643' 
  AND token = '9wv+hFVkOKnDuCrfrLHP18GFw7Tw8XPVM9VR2G2ZBmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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