SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9f0d6a7fad1eaa08106425c3472d591be24164542ac0474b23dd02ca275055b' 
  AND token = 'Gpux7Qb/hZV4jyTfjhTEY2esi4dRkun+Phlf7WxGO0M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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