SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3726ab74eb091e4aba098b2e4a38c99f7525e8ad9a00a4c4461708c77a74cf37' 
  AND token = 'lSf3muXaxcnjHLZXooM0OFw2IbcVySSE+rbPB18pJRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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