SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd879c147a4966375849feb081734734b15d019c8ba39fe896a1cb3ee0b3b4d3' 
  AND token = 'VHQV5JPY1mu4NxkimFK9nK8HOXtaOsdDJxDcojZAphE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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