SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52c2414321ed58a26833d5c7aba3c9965044bd54750c158be1813d13569b24ee' 
  AND token = 'IzSMWtw6kshUsAITaYskgvD/9SIjnRFCmCjhnVn0QrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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