SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd45cf1d5de35216d4fbb27c75da75d21070688c2ebb7fab87447ee521eba6e73' 
  AND token = 'paUhAloE1jqVMJGRR+T3VKTUD1kFlgWl+0CnSDOF4cw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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