SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65272f49b8a511005a9adc28360418b42bc88f3686ac0c231720a5b98baffde9' 
  AND token = 'DY1jJSBKunlPhCc861XVxOIu9nm3990Xu/kOGs2MSVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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