SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '493df17f292046c23af3bfd870495e520faef613f78ded4752d255a74681afbb' 
  AND token = 'Si1jQsE62eYp+D/CzOiadiwwnkV4loa0u7FEQDoo1jA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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