SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '540133a9ce7cb8260d457098220dde27e57daf9ba2986f2bf1f850955888af05' 
  AND token = 'T4L3cDt+inPYA9njhWiZw4gQfKEJkSrhx2TYZEe8Yaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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