SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8becd5f7588430ad8b2fd91ef2032b46d80493662a89f912c66bbb3effc22a3c' 
  AND token = 'yS+D2tvJcopt35+nKZvh0IfKhft6BGaiEKFRO9a/uas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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