SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d3f9fad0a8afccd4278201f10c2d302b9f97a450d195f9c1624cb24256ca5f8' 
  AND token = 'L9lc79ZIjZtH501pNaE/9IAibVFXENbP7iPUrvcAELw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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