SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f680833c621c807c4ee926805775f3cb8f225f5c2cacdec158a56b40d60ab88' 
  AND token = 'srd9mlU/y/jylW6GJUVceTIO+gg38vPMd+Ou8fUfZjg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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