SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8077defc1a2a144987d7a743ccb3198277a95e396aa7744f567254f278a531ba' 
  AND token = 'put7wy95zW7B8gLeORJsmPrxpvaQIegSg5xmLD12XpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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