SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afa310ae633584fe3227c984a5fde9a34ea55f1f70d0e620c2e20c2128364fe9' 
  AND token = 'J/E4rC+Scwsp0QCeD3wMD6Iao7DMb6LFzn+ysh/0neY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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