SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '639debd48ecaf452cd170a58e2d9200445883b562bc75fac5a3b4380c54a8913' 
  AND token = '0o4D59kW4BDV2eqYMV0WjnUBVKugxYHH08J6UXMghX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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