SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56fe3c6fb713f0bb64e982202d8eddf252a57d86d7962ff95611c5c22a9d3c45' 
  AND token = 'OxYfqW0TjlWWRhEF+7XgatI9dLLAf03a4RBMc/OV0oY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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