SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9be678e3d28f5a62292670c2b58c2f86768d2d1b2f42a420b69867677457565' 
  AND token = 'vcBF27cHJAdpsqPjM0m2UW/GmZoYKNtVuAXJgUWjF4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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