SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c1598017245303e2f257cb2a10bb68836509e9484e9a26773b52f8564d65cc2' 
  AND token = 'qt+GgKKCUiiz7TwsmyQyOwkVLWiUq1bEZ/2G48q9Lt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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