SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '141ca97729a12bb0412749d31daae57846ee77355a752a6c1518081f539a14aa' 
  AND token = 'ypwVGlOHY1VmWX1SsVNG2PgqWw0IKib+WhFLtHX+RCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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