SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8b400a3e770a9daae096889e709289a6d042c2e0e944f33f0d850471240c97a' 
  AND token = 'IwW/uKiEqqVLf4lYKMd9r8mCtV3RmKHNiWigahyG0oE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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