SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d2555f2862d3d8b64247c58eb28e4b9719052cd1e6ae9a940111c216698dbc2' 
  AND token = 'cDJ1QVwiRSqDZYIQ+GxubKbvK5CTvxwr9IhDGlRAWLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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